1. Field of the Invention
The present invention relates generally to video processors, and more specifically to a technique for efficient utilization of a field memory for storing video signals.
2. Description of the Related Art
In conventional video processors, an analog composite color video signal is converted to a digital signal and all information contained in each field of the video signal are stored into a field memory and successively read out of the memory for digital-to-analog conversion. The use of the field memory is to provide features such as noise reduction and production of frozen and mosaic pictures. An address counter is provided in the field memory to provide read/write control. To determine the actual size of the field memory, the address counter is reset in response to a vertical sync pulse separated from the composite video signal. In addition to the picture information, the field information stored in the current field memory contains vertical and horizontal synchronizing signals whose waveforms are strictly specified according to the NTSC or PAL standard. Therefore, part of the field memory is always occupied by the signals which do not contribute to picture quality.